Double window



Jan. 19, 1943. H. HERTEL ET A1,. 2,308,918

DOUBLE WINDOW Filed neo. 5, 1940 /I /f I f ,//fi\\grl///////////////////// Patented Jan. 19, 1943 DOUBLE WINDOWHeinrich Hertel and Justus Muttray, Dessau, Germany; vested in the AlienPrope'` ty Custodian Application December 5, 1940, Serial No. 368,558 InGermany September 28, 1939 1 Claim.

This invention relates to improvements in double windows, and refersparticularly to a double window construction intended for use onairplanes and especially on those intended .to fly at high altitudes.

Vehicles have already been equipped with double windows having a gastight space enclosed between them which could be heated. Dry gas wasinjected and heated therein to prevent condensation on the panes. Suchwindows, however, when applied ,to airplanes are open to the objectionthat it is necessary to employ very thick glass because of thedifferences between the air pressures exerted upon the panes and thepressure of the gas exerted upon the latter, .thereby materiallyincreasing the weight oi the windows. Spacing members have also beenemployed to reinforce the panes and permit the use of thinner glass butsuch an arrangement produces interrupted vision, and the spacing membersare difficult to fasten satisfactorily.

Double windows 'have also been utilized Where the 'panes were subjectedto only slight differences in air pressure and were made of special thinglass of high tensile strength and high elasticity to withstand suchslight differences; but

when such windows are employed in airplanes flying at high altitudes somuch deformation occurs, due to variation in air pressures, that visionis so distorted as to render it unsafe to use them for cockpits. Doublewindows having a gas tight seal between the panes and means forsubstantially equali'zing the pressure of the gas and that of the airexerted on both panes, which in that instance is the same, have beenemployed on ground vehicles.

This invention aims to provide a double window which is light inlweight, and which adords good insulation and unhindered vision withoutdistortion.

Another object of the invention is to provide' a double windowconsisting of a thicker outer pane to resist stresses caused bydifferences in air pressure inside and out, and a thinner inner paneyieldingly mounted relative to .the outer pane whereby the pressure ofgas sealed in the chamber between the panes is automatically equalizedwith the air pressure exerted against the oppo site side o! the innerpane.

A further object of .the invention is to provide a double window havingan outer pane thick enough to protect the inner pane from all stressesresulting from differences in air pressure, thereby permitting the useof a very thin inner pane which requires no reinforcement which would varound the outer pane so that gas tight seal is positively maintained atall times between the panes.

Having thus enumerated some of the major objects and advantages of theinvention we will now proceed to describe a preferred embodiment of thedouble window'with the aid of the drawing wherein a sectional viewthereof is shown.

Referring to the drawing, I designates an outer frame having arelatively .thin inwardly directed ange 5 formed substantially flushwith its outer face, and secured to the inner face of the said outerframe is an .inner frame 6 all the sides of which project inwardlybeyond the sides of the outer frame 5. Mounted in the latter .is a thickouter plane having an annular recess la formed around its outer edge toreceive the annular flange 5 so that the outer faces of the frame 4, theflange 5 and the pane i are all substantially in alignment. The innerside of the outer pane I is marginally supported by the inner frame 6.

One extremity of an annular bellows-like resilient mounting. I6 is heldbetween the nange 5 and the recessed portion la. of the outer pane. Thismounting is flexed and. supported both between the peripheral margin ofthe pane l and .the adjacent portion of the frame 4, and between theinner face of the said outer pane and the adjacent face of the innerframed The rearwardly intermediate portion of the mounting I8 is foldedoutwardly towards the wall of the opening through the inner frame 8 andter minates in an inwardly folded extremity to which an inner pane,which is relatively quite thin, is marginally secured to form a gastight chamber I between the panes l and 2.

From the foregoing it will be readily seen that due to the resilience oithe bellows-like mounting IB the pane 2 is automatically moved toequalize the gas pressure within the chamber 3 with the air pressureacting upon the inner face of .the inner pane 2, thereby increasing ordecreasing the volume of the said chamber. Again due to the mounting ofthe outer pane I in the folded outer portion of the mounting I8 so thata joint is made between the latter and the inner face of the outer panethe folded intermediate portion of the mounting is in no way dependentupon the wall opening of the inner frame to Seal the chamber and may beor such size as to be clear of .the said wall at ail positions of theinner pane 2,

While in the oregoing the preferred arrangement of the invention hasbeen described and shown, it is understood that the construction issusceptible to such alterations and modifications as fall within thescope of the appended claim.

What we claim is:

A double window construction comprising an outer frame having a ledgealong one side ot its inner periphery, an inner frame in juxtapositionwith said outer frame and forming with said other margin of saidresilient mounting 'being secured to the outer tace or the inner pane.

HEINRICH HERTEL. JUSTUS MU'I'IRAY.

